v3.26.1
(Re)Insurance contracts and investment contracts with discretionary participation features - Summary of Assets and Liabilities for Groups of Insurance Contracts Issued and Reinsurance Contracts Held by Measurement Model (Detail) - EUR (€)
€ in Millions
Jun. 30, 2026
Dec. 31, 2025
Disclosure In Tabular Form Of Insurance Contracts And Reinsurance Contracts Assets And Liabilities Based On The Approach [Line Items]    
Insurance contract assets € 16 € 18
Insurance contract liabilities 137,407 176,067
Insurance contracts net balance 137,391 176,049
Reinsurance contract assets 17,374 17,153
Reinsurance contract liabilities 201 195
Reinsurance contracts net balance 17,173 16,958
Contracts not measured under the PAA [member]    
Disclosure In Tabular Form Of Insurance Contracts And Reinsurance Contracts Assets And Liabilities Based On The Approach [Line Items]    
Insurance contract assets 16 18
Insurance contract liabilities 137,357 176,024
Insurance contracts net balance 137,341 176,006
Reinsurance contract assets 17,365 17,146
Reinsurance contract liabilities 201 195
Reinsurance contracts net balance 17,164 16,950
Contracts measured under the PAA [member]    
Disclosure In Tabular Form Of Insurance Contracts And Reinsurance Contracts Assets And Liabilities Based On The Approach [Line Items]    
Insurance contract assets 0 0
Insurance contract liabilities 50 44
Insurance contracts net balance 50 44
Reinsurance contract assets 9 8
Reinsurance contract liabilities 0 0
Reinsurance contracts net balance € 9 € 8